fn getNode = (refs.dependentnodes this)[1]
andlocal node = getNode() --firstonly:on
It worcks, but I personaly don´t see any advantages aver that other code with arrow mesh helper, I mean it´s still a wire arrow and not a solid one and there still no way to see where the front and back side of the arrow is.

to learn how to make tools, study the subject and develop the tool yourself

to find someone who interesting in tools development practicing, interest him in your task and wait for the solution

to order a solution to a professional, and pay for the entire development cycle

the two first solution don’t exist, as i understand.
the third solution is not suitable for you for some reason.
the fourth doesn’t work for your because it’s not complete.
the fifth solution, if you bear in mind me, you obviously can’t afford.

what do we have to do in this case?

the fourth solution still leaves me some sense, but only in combination with the third.make two wire arrows yourself using my snippet, then we can continue.

if, in order to start the car, i will do pulling out some wires and hoses from under the hood, will this help?

I see your point, but saw no other way to make it worck and that lines of code were of no use for me since I didn´t even understand what they were doing. Now I got a really simple example of solid mesh helper: